If Liberals Voted ...

A voter in Columbus, Ohio, on Election Day in 2016.CreditMaddie McGarvey for The New York Times

If liberals voted at the same rate as conservatives, Hillary Clinton would be president. Even with Donald Trump’s working-class appeal, Clinton could have swept Michigan, Wisconsin and Pennsylvania.

If liberals voted at the same rate as conservatives, Democrats would control the Senate. Clinton or Barack Obama could then have filled the recent Supreme Court vacancy, and that justice would hold the tiebreaking vote on campaign finance, labor unions and other issues.

On Tuesday, the northern suburbs of Atlanta will hold the country’s most significant election since Trump’s victory. It’s a special election in a conservative-leaning district once represented by Newt Gingrich and until recently by Tom Price, an architect of a health care plan that would take insurance from millions.

Special elections aren’t normal. They can attract far more attention and money than a typical House race does, and the Georgia race has. Yet it nonetheless offers a tantalizing lesson for Democrats.

Their candidate, Jon Ossoff, has a real chance to win partly because he isn’t suffering from the gap in voter passion and commitment that usually bedevils Democrats, especially in off-year races. It would be a big deal if Democrats could more often close their passion-and-commitment gap. Even modestly higher turnout could help them at every level of politics and hasten the policy changes that liberals dream about.

After all, polls show that a majority of Americans supportprogressivepositions on most big issues. Yet Republicans dominate state and federal government.

Turnout is a big reason. Last year, Americans between the ages of 18 and 24 voted for Clinton over Trump in a landslide. Only 43 percent of citizens in that age group voted, however. By contrast, Americans over age 65 supported Trump — and 71 percent of them voted. Similarly, Americans in their 30s were more likely to support Clinton, and less likely to vote, than those in their 50s.

The pattern also exists across ethnic groups. Asian and Hispanic voters went for Clinton in a bigger landslide than millennials, but most Asian and Hispanic citizens didn’t vote.

And the gaps grow even larger in midterm elections. A mere 17 percent — 17 percent! — of Americans between 18 and 24 voted in 2014, compared with 59 percent of seniors.

If you’re liberal and frustrated by these statistics, you should be. But you shouldn’t be defeatist.

What can be done? First, don’t make the mistake of blaming everything on nefarious Republicans. Yes, Republicans have gerrymandered districts and shamefully suppressed votes (and Democrats should keep pushing for laws that make voting easier). But the turnout gap is bigger than any Republican scheme.

Second, keep in mind that turnout is a human-behavior problem. It involves persuading people to change long-established habits. And there is a powerful force uprooting all kinds of habits today: digital technology.

More specifically, smartphones are changing how people interact with information. I’d encourage progressives in Silicon Valley to think of voting as a giant realm ripe for disruption. Academic research by Alan Gerber, Donald Green and others has shown that peer pressure can lift turnout. Smartphones are the most efficient peer-pressure device ever invented, but no one has figured out how social media or texting can get a lot more people to the polls — yet.

Finally, remember that the political left has had some recent successes in raising turnout, and they involved old-fashioned political excitement. Obama won partly through higher turnout among younger and nonwhite voters. Black turnout even exceeded white turnout in 2012, before slipping last year.

This month’s British election is also intriguing. The Labour Party did better than expected, helped by a surge of younger voters angry about Brexit. But Britain also offers a caution to anyone who thinks higher turnout depends on far-left candidates, like Jeremy Corbyn, the Labour leader. Corbyn didn’t win, and he didn’t come very close.

My instinct is that the answer for Democrats involves a passionate message of fairness — of providing jobs, lifting wages, protecting rights and fighting Trump’s plutocracy. It can be bolder than Democrats have been in decades. But it should not resemble a complete progressive wish list, which could turn off swing voters without even raising turnout.

People who don’t vote regularly aren’t progressive activists in disguise. They tend not to follow politics closely. Although most lean left, they are not doctrinaire, and they’re not looking for white papers. They are looking to be inspired.

Obviously, these are tough times for Democrats. They haven’t had much electoral cheer since 2012 — and it’s unclear whether Ossoff will win. But Democrats should remember that they still have one enormous advantage.

The country’s real silent majority prefers Democrats, if only that majority could be stirred to vote.